This invention relates to a telescopic joint which enables its telescopic parts to be rapidly, easily, economically, effectively and adequately locked in position, thereby facilitating the repair of underwater pipelines even if laid at great depth.
The cycle of operations necessary for repairing a damaged underwater pipeline is known to comprise cutting-away the damaged piece of pipeline, joining an outer sleeve in a sealed manner to each of the cut ends of the pipeline, then joining together the made-up ends of the pipeline by means of an intermediate pipe portion prepared on the surface and locked in a sealed manner between the sleeves.
However, in order to be able to compensate for inevitable errors in measuring the distance between the cut ends, this intermediate portion must necessarily contain a telescopic joint which has to be locked in position in a sealed manner when the intermediate portion has been inserted and locked onto the two end sleeves.
Various types of telescopic joint used for repairing underwater pipelines are already known in the state of the art.
These known telescopic joints, which are constituted substantially by two cylindrical parts slidable within each other and capable of being locked hermetically together when correctly positioned in the axial direction, all have in common the fact that they internally comprise complicated sealing and anti-sliding elements which are operated hydraulically.
They therefore all have the double drawback of being complicated and expensive, and of providing an inadequate seal by virtue of its very small length, the seal being limited to those specific points at which the sealing elements are made to act.